Dynamic combustion characteristics in a rectangular supersonic combustor with single-side expansion

摘要

Dynamic combustion characteristics of a rectangular scramjet combustor with single-side expansion were studied experimentally and numerically. Experiments were implemented with an isolator entrance Mach number of 3.46, and an air stagnation temperature of 1430K. Ethylene was utilized to fuel the combustor over an equivalence ratio range of 0.20hi<0.63. Results indicated that the combustion modes varied from different equivalence ratios. For an intermediate phi=0.375, an intermittent dynamic combustion occurred. During the dynamic process, the flame sometimes stabilized in the jet wake of the top cavity, and at other time it oscillated between dual parallel cavities. The pseudo-shock train traveled periodically along the length of the combustor, and the penetration depths of the two injectors exchanged. Quantitative analysis illustrated that the average frequency of unsteady combustion was approximately 200Hz. The reason for the occurrence of the self-sustained dynamic process was related to the interactions between the shock-induced separated region and heat release.